Fullerton wrote that many House Republicans called his office to keep the parks open "because they knew the shutdown they created would hurt them at home."

“They wanted police or sheriffs to man the parks with rangers on furlough. But they don’t know the area or terrain, so it’s still very dangerous to do that,” he wrote. “They’re playing with fire here and it’s incredibly unsafe.”

They wanted police or sheriffs to man the parks with rangers on furlough. But they don’t know the area or terrain, so it’s still very dangerous to do that. They’re playing with fire here and it’s incredibly unsafe.

The National Park Service will keep its gates to the country’s parks open until the government reopens but will close any facilities — including bathrooms, visitors centers and campgrounds — that require staff. National Park Service employees will be on furlough.

The Interior Department kept park gates open during a shutdown in January of this year, which led to a number of land misuses, including the illegal hunting of a pregnant elk in Utah's Zion National Park and a snowmobiler coming too close to Yellowstone National Park's Old Faithful geyser.

Environmental and conversation groups have expressed concern about parks remaining open without trained staff on site.

“Visitors from around the world who have planned their trips to our national parks months in advance now face the possibility of disruption and disappointment when they arrive at parks only to find closed visitor centers, locked restrooms and unplowed roads,” Theresa Pierno, president of the National Parks Conservation Association, said in a statement.

The Interior Department is one of several federal agencies that closed when Congress failed to meet a midnight deadline on Friday to fund them.